Traditional vine wire support posts are generally made of either metal or wood.
They are used to support the wire on which vines are supported during the fruit growing season. The post is used to prop up the wire and vine at 4.5 m to 6.0 m spacing between two end supports which are generally spaced between 100 m to 300 m apart. The posts generally have six wires to support, one for the irrigation tube, one for the main vine and four to support and train the foliage. The foliage wires are lowered and raised every year between pruning and harvesting. The loads applied to these posts are a nominally 20 kg/m vertical downward dead load and effectively 30% to 50% frontal area for wind loading. In many cases the top of the post is used to support netting to protect the fruit from damage due to birds and other fruit eating vermin.
In the case of the wooden posts, additional hardware in the form of support attachments are used to support the wire. The support clips are used to support the foliage wires and the staples are used to support the irrigation tube wire and the main vine wire. The support clips are fragile and subject to failure requiring replacement on a regular basis. The staples are prone to being driven in too far during initial installation. This causes excessive point loading of the wire and subsequent failure. The posthole must be bored into the ground and then the post is hammered into the hole. The installation process is time consuming and labour intensive. During harvesting the harvester uses a vigorous “to and fro” action to shake any fruit from the vines. The wooden post is rigid. It does not move “to and fro” with the vine and wire. Due to this a fair percentage of fruit is not collected, and left on the vine to rot. From time to time the movement of machinery throughout the vines will result in collision with the post. When this occurs the post is usually broken at ground level, thus requiring replacement.
In the case of the metal posts, the nature of the pressed metal form and its sharp edges cause the wire galvanising to be scratched off. This initiates rust in the wire and creates premature failure of the tension wires. Typically the post must be hammered into the ground for installation. However the post may be subject to sinking into the ground due to the “to and fro” motion of the harvest process and the natural frequency of the vines when subject to wind loadings. Furthermore during installation they tend to twist thus causing misalignment. From time to time, the movement of machinery throughout the vines will result in collision with the post and the post is usually permanently bent at ground level thus requiring replacement. The metal posts do not lend themselves to netting as the metal is too sharp and penetrates the netting.
It is an object of the invention to provide a vine wire support post which obviates or reduces one or more or the aforesaid difficulties or disadvantages.